a.draw a process tree. denote the process in the tree as p1, p2,..

b. for the message at lines A and B, how many times will each message be displayed, and which process output the message at line A and B, respectively?

how many unique threads are created and which process creats threads?

pid_t pid:

fork();

printf("line A"); /*A*/

pid = fork();

if (pid>0) {\printf("lineB"); /*B*/

fork();

threads_creats(...);

}